Showing papers by "University of Peradeniya published in 1990"
TL;DR: The combined use of physical and chemical treatment procedures appear to provide a better prospect than the use of only a single treatment procedure for detoxification of aflatoxin B1 in foods and feeds.
238 citations
TL;DR: The visceral leishmaniasis vector Phlebotomus argentipes Annandale & Brunetti is widely distributed throughout the Indian sub‐continent and S.E. Asia and has been attributed to the zoophilic nature of P.argentipes, since they were not recorded biting man.
Abstract: The visceral leishmaniasis (VL) vector Phlebotomus argentipes Annandale & Brunetti is widely distributed throughout the Indian sub-continent and S.E. Asia. The absence of VL in areas such as Sri Lanka has been attributed to the zoophilic nature of P.argentipes, since they were not recorded biting man. Field studies on P.argentipes were undertaken in the central highlands of Sri Lanka, near Kandy, in May 1988. Male sandflies outnumbered females on cows by 19:1, and were regularly spaced at all densities. This behaviour is considered analagous to swarming in other Nematocera. However, all-night human-biting catches show the biting rate to be similar (mean = 8.4, range 2-25 bites per night over ten consecutive nights) to that in N.E. India where VL is endemic. This anthropophagy was maintained during laboratory colonization.
83 citations
TL;DR: The angiosperm flora of Sri Lanka has been comparatively well studied by many eminent botanists for over two centuries, which has a rich endemic component and also exhibits strong affinities to that of peninsular India as mentioned in this paper.
Abstract: The angiosperm flora of Sri Lanka, which has been comparatively well studied by many eminent botanists for over two centuries, has a rich endemic component and also exhibits strong affinities to that of peninsular India Some of the 15 floristic regions recognized in the island have exceptionally rich, highly localized floras. But increased forest disturbances over the years have taken a heavy toll. A plea is made to conserve at least one sufficiently large forest reserve in each floristic region. A meaningful conservation program has been launched in the Sinharaja MAB Reserve; similar programs are urgently needed for other protected areas of the island.
80 citations
TL;DR: In this paper, a damage model for monotonic and cyclic behavior of concrete is developed, which recognizes the tortuous nature of cracks in compression, which affects the flexibility of the material in a direction coinciding with the average plane of cracks.
Abstract: A damage model for monotonic and cyclic behavior of concrete is developed. The model recognizes the tortuous nature of cracks in compression, which affects the flexibility of the material in a direction coinciding with the average plane of the cracks. An elastic potential is introduced in terms of the principal stresses and a compliance tensor dependent on the accumulated damage. Damage evolution is obtained using a loading surface and bounding surface, defined in terms of the thermodynamic force conjugates of the damage variables. The damage growth during a series of unaxial compression and cyclic tests is inferred from the amplitude attenuation of ultrasonic waveforms transmitted laterally through the specimen while the tests are in progress. The behavior of concrete under compression, tension, biaxial loading and cycling, and damage growth under both monotonic and cyclic loading are found to be predicted well by the proposed theory.
76 citations
TL;DR: Irrigation development led to reduced breeding by the majority of species; however, most species that did increase in prevalence were potential vectors of human disease.
Abstract: A survey of ground water-breeding mosquitoes was done during 1986–1987 in an area undergoing irrigation development in the Mahaweli Project of Sri Lanka. Forty-nine species were collected during the 12-mo phase of human settlement and infrastructure construction, and 42 species during the succeeding 12-mo period under irrigated rice culture. Development resulted in the elimination of some preexisting breeding habitats, the modification of others, and the creation of new habitats. The overall change from uninhabited forest to settled irrigated rice sharply increased the prevalence of Anopheles annularis van der Wulp, An. peditaeniatus (Leicester), Aedeomyia catasticta Knab, Mimomyia hybrida (Leicester), Mansonia uniformis (Theobald), and Culex tritaeniorhynchus Giles. Equally sharp decreases occurred in the prevalence of An. barbirostris van der Wulp, An. barbumbrosus Strickland & Choudhury, Ae. jamesi (Edwards), Ae. vittatus (Bigot), Ae. pseudomediofasciatus (Theobald), Cx. halifaxii Theobald, Cx. malayi (Leicester), Cx. minutissimus (Theobald), Cx. nigropunctatus Edwards, Cx. fuscocephala Theobald, and Cx. mimulus Edwards. Other species that showed smaller positive or negative changes included An. nigerrimus Giles, An. culicifacies Giles, An. jamesii Theobald, An. subpictus Grassi, An. vagus Donitz, An. varuna Iyengar, Mi. chamberlaini (Ludlow), Ma. annulifera (Theobald), Cx. bitaeniorhynchus Giles, Cx. gelidus Theobald, and Cx. pseudovishnui Colless. Irrigation development led to reduced breeding by the majority of species; however, most species that did increase in prevalence were potential vectors of human disease. Components of the irrigation system such as reservoir and canal margins, seepages, and rice fields provided increased breeding sites for some of these species.
64 citations
TL;DR: A series of 21 cases of adenomatoid odontogenic tumour is reported from Sri Lanka, and there were no recurrences following conservative surgery in follow-up periods ranging from 2 to 11 years.
59 citations
Journal Article•
TL;DR: In Sri Lanka, the feasibility of using primary health care workers for oral cancer and precancer screening was pilot tested between 1980 and 1982 and the categories of false positives referred and the false negatives detected following screening were analyzed in detail.
Abstract: The accuracy of the field diagnosis is of crucial importance in the successful implementation of a screening programme. In Sri Lanka, the feasibility of using primary health care workers for oral cancer and precancer screening was pilot tested between 1980 and 1982. This paper analyses in detail the categories of false positives referred and the false negatives detected following screening. Among 660 subjects who arrived at the referral centre following screening, 64 (10 per cent) had no apparent oral lesion. The predictive value determined in this study was 58 per cent for a referrable lesion and 98 per cent for non referrable cases.
57 citations
Journal Article•
TL;DR: A light microscopic morphometric analysis of the development of the mouse submandibular gland has been carried out from birth up to the age of 6 weeks, finding sexual dimorphism is clearly evident in the gland at 4 weeks of age.
Abstract: A light microscopic morphometric analysis of the development of the mouse submandibular gland has been carried out from birth up to the age of 6 weeks. At birth the bulk of the gland consists of approximately equal volume proportions of acinar, terminal tubule and non-secretory cells. The granular convoluted tubule is absent at birth. The neonatal female gland resembles that of the male in many respects. With the regression of the terminal tubule at 2 weeks of age the duct system of the gland is seen to differentiate into excretory, striated and intercalated ducts. The volume proportions of the gland constituents of the female are similar to those of the male at 2 weeks. At this age, the acini occupy 55%, the striated duct 20% and the intercalated duct 15% of the total gland volume. Sexual dimorphism is clearly evident in the gland at 4 weeks of age when the duct system is seen to differentiate to form its granular convoluted tubule component. The granular tubule occupied 19% of the gland volume in the male but only 8% in the female at 4 weeks. The proportions of acini are only 41% in the total gland volume of the male mouse but 62% in the female at 4 weeks. In the male gland the proportions of granular convoluted tubule increase from 13% to 21% between 4 and 6 weeks and the secretory granule content of these cells from 6% to 24%. At 6 weeks of age the volume proportion of granular convoluted tubule in the male is 45% and that in the female is only 12%. At this age the acini occupy a proportion of 30% in the male gland as opposed to 57% in the female gland. At 6 weeks the volume of granular convoluted tubule cells is 40% lower in the female (1842 microns 3) than in the male gland (2995 microns 3).
53 citations
TL;DR: In this article, the effects of magnesium dopant level, calcination temperature, duration of heating of the catalyst and pH affect the ammonia yield, and the optimum conditions were 2-4% magnesium doping level and heating at 500°C for 2 h.
45 citations
TL;DR: Analysis of the data by division of high density lipoprotein-cholesterol levels into tertiles showed a trend of a higher frequency of B1 allele (presence of the TaqIB site) with reduced high densitylipoprotein levels, which was more frequent in control subjects, but not in coronary heart disease patients.
43 citations
TL;DR: Growth, determined by viable plate counts, indicated that maximum growth in all the treatments reached 109 CFU/g, irrespective of the initial spore load, and mycelial growth and sporulation occurred faster at 35°C at all spore levels than at 28°C.
TL;DR: In this paper, a seamless tube mill rolling process was simulated with the aim of designing alloys and schedules for the production of as-hot-rolled yield strength levels which are currently attained only by quenching and tempering.
Abstract: A seamless tube mill rolling process was simulated with the aim of designing alloys and schedules for the production of as-hot-rolled yield strength levels which are currently attained only by quenching and tempering. Tests were performed on four candidate Ti-V-N steels with two levels each of carbon (0.10 and 0.18 wt pct) and vanadium (0.10 and 0.16 wt pct). Two different types of schedule were used: (1) a high-temperature schedule, corresponding to the production of large tube diameters, which utilizes the principles of recrystallization-controlled rolling (RCR) and (2) a second (for small tubes), which relies ondynamic recrystallization-controlled rolling (DRCR). The DRCR schedule, together with the higher cooling rate achievable on the smaller tube sizes, produces a much finer ferrite grain size than the RCR schedule. However, this is largely offset by increased strengthening in the RCR structurevia precipitation hardening. As-hot-rolled yield strengths in the range of 483 to 715 MPa (70 to 104 ksi) can be achieved using either type of schedule.
TL;DR: Studies on 10 cows showed that a few larvae occur in the colostrum of some cows before the calf has suckled, but most are present from the day after calving and for a further five days, which determines the optimum time for treating calves.
TL;DR: A procedure for labelling hatched Toxocara vitulorum larvae with 75 selenium with an enhanced fluorographic autoradiographic procedure to study the dynamics of the infection in non-pregnant and pregnant buffalo.
TL;DR: The very high prevalence of eating epilepsy in the present series could pathogenically be related to genetic or ethnic factors and to the bulky meals rich in carbohydrates consumed by the patients.
TL;DR: It was concluded that the drop in egg counts was the result of reduced fecundity and the fertility of the eggs from faeces was greater than 92% throughout.
TL;DR: The protective exoskeleton appeared to prevent fungal growth on dried shrimp, and species of Aspergillus niger, A. flavus, and Aureobasidium did not grow on dried-fish under laboratory conditions.
Abstract: The mycoflora of dried-salted fish from markets in Kandy, Sri Lanka was studied with emphasis on visibly spoiled dried fish. A total of 61 fungal isolates from 25 dried-fish were isolated and identified. The most prevalent fungus was Aspergillus niger. Species of Aspergillus flavus, A. fumigatus, A. glaucus, A. restrictus, Aureobasidium spp. Basipetospora halophila (a genuinely halophilic fungus) Cladosporium herbarum, Gliomastix, spp., Penicillium chalybeum and Penicillium expansum were present. The isolated fungi did not grow in synthetic media containing more than 30% sodium chloride. Aureobasidium spp. and Gliomastix spp. did not grow on dried-fish under laboratory conditions. The protective exoskeleton appeared to prevent fungal growth on dried shrimp. The A. flavus strains isolated were not aflatoxigenic.
TL;DR: Euodia lunu-ankenda root bark contained two fungicidal phenylethanones, 1-[2′,4′-dihydroxy]-6′-(3′-methyl-2′-butenyloxy)-5′-( 3′,methyl- 2′-Butenyl)]phenylethanone and
TL;DR: The root bark of Pleiospermium alatum afforded five alkaloids, five coumarins, lupeol and stigmasterol as discussed by the authors, and one of the acridones was a new compound.
TL;DR: Quinone-methide and phenolic triterpenoids of the root outer bark of Celastrus paniculatus have been identified as celastrol, pristimerin, zeylasterone andZeylasteral whereas those of Kokoona reflexa rootouter bark were pristinerin, Zeylaster one and zeylastersal.
TL;DR: The study demonstrates sibling clustering in a partial epilepsy, implicating for the first time genetic susceptibility in the aetiology of eating epilepsy.
Abstract: Eating-related seizures affecting 20 individuals among 59 siblings belonging to nine families are presented. The type of epilepsy was partial in all the affected individuals, and the seizures complex in 15 and simple in 5, secondarily generalized in the majority. The onset of epilepsy, in most cases, was in the second decade of life. A remarkable degree of intra-family consistency was observed with regard to age at onset, symptomatology of seizures and timing of eating seizures. The study demonstrates sibling clustering in a partial epilepsy, implicating for the first time genetic susceptibility in the aetiology of eating epilepsy.
TL;DR: Steam distillates collected from leaves of Rutaceous plants by Simple Steam Distillation method have been investigated for antimicrobid and insecticidal activity and high antibacterial activity was displayed by L. acidissima and M. paniculata against Staphylococcus aureus.
Abstract: Some steam distillates collected from leaves of ten Rutaceous plants by Simple Steam Distillation method have been investigated for antimicrobid and insecticidal activity. Murraya paniculata, Toddalia asiatica, Lirnonia acidissima and Glycosmis pentaphylla have shown significant anti fungal activity against Cladosporium cladosponoides. High antibacterial activity was displayed by L. acidissima and M. paniculata against Staphylococcus aureus. Atalantia monophylla and Acronychia pedunculata caused significant mortality of the aphid. Aphis craccivora.
TL;DR: In this paper, the authors measured the nitrogenase activity in the surface soil and litter layers from a tropical lowland rain forest and an adjacent fernland in Sri Lanka by the acetylene reduction method.
Abstract: Nitrogenase activity in the surface soil and litter layers from a tropical lowland rain forest and an adjacent fernland in Sri Lanka was measured by the acetylene reduction method. The total amount of acetylene reduced, a measure of biological nitrogen fixation, was greater in the fernland (38.4 µmol m−2 h−1) than in the forest (15.3–29.2 µmol m−2 h−1). In both ecosystems the nitrogenase activity was greater (59–85%) in the soil than in the litter layer. The rates of acetylene reduction in soil and litter showed an inverse relationship with the decay constants of mixed litter and a positive relationship was found between the rate of acetylene reduction and the C:extractable nitrogen ratio of the soil. The relatively greater rate of nitro genase activity coupled with the slower rate of litter decomposition in the fernland indicates that accumulation of nitrogen may result in the soil and litter layers of the deforested areas during their aggrading phases.
TL;DR: Two new anthocyanins, cyanidin and peonidin 3-gentiobioside acylated with sinapic acid, have been isolated from the tuber of Dioscorea alata L. ‘King yam’ originated from Sri Lanka.
TL;DR: A water-soluble arabinoxylan was isolated from the mucilaginous bark of Litsea glutinosa (Lauraceae) and indicated a backbone of (1----4)-linked beta-D-xylopranosyl residues substituted at both positions 2 and 3 with side chains composed of either single or (1 ----3)-linked arabinofuranosyl residues.
TL;DR: In this article, the authors conducted a study to study drug use before hospital admission and drug prescribing in wards among 850 randomly chosen inpatients in Sri Lanka and found that during the 48 h before admission drugs were used by 84% of the patients, of whom 73% took Western and 29% Ayurvedic drugs: combinations were common.
Abstract: Few drug utilization studies have been conducted in Sri Lanka and they were register based. We wished to combine records with interviews to study drug use before hospital admission and drug prescribing in wards among 850 randomly chosen inpatients. Four institutions representing different levels of health care were studied. At the end of the study, all 25 practitioners involved were interviewed about how they perceived their prescribing practices. During the 48 h before admission drugs were used by 84% of the patients, of whom 73% took Western and 29% Ayurvedic drugs: combinations were common. The drugs most commonly named were aspirin and paracetamol. The medical records were an unreliable source of information in this respect. Infectious and parasitic disorders, together with respiratory diseases, constituted 40% of the diagnoses. The total number of prescriptions was 3,226. The number of drugs prescribed per patient varied between the institutions, the two extremes being the University (2.7) and the peripheral unit (5.1). Analgesics--antipyretics was the most commonly prescribed class at all institutions, 45.7% and 86%, respectively, of the patients being exposed to these drugs at the two institutions. The prescribing of antibiotics (53%) and antihistamines (65%) was considerably more common in the peripheral unit. The most commonly prescribed single drug products were paracetamol (31.3%), aspirin (20.9%), diazepam (21.8%), chloroquine (14.5%), ampicillin and multivitamins (both 12.6%). Most practitioners indicated deliberate use of active drugs as placebos, one drug chosen being vitamin. They were aware of the need for drug information from sources other than the industry.(ABSTRACT TRUNCATED AT 250 WORDS)
TL;DR: The total synthesis of (E)-Suberenol (1) was carried out under the conditions of palladium-catalysed Heck condensation as discussed by the authors, and two new coumarins, cyclobisuberodiene (2) were synthesised from suberenol.
TL;DR: Buffalo aged 3–15 months on institutional farms and in the villages of an irrigation project were monitored for gastrointestinal nematodes by faecal egg counts over two years, demonstrating that the eggs which were present were produced by mixed infections of small numbers of Haemonchus, Mecistocirrus digitatus, Trichostrongylus, Bunostomum phlebotomum and Cooperia spp.
Abstract: Buffalo aged 3–15 months on institutional farms and in the villages of an irrigation project were monitored for gastrointestinal nematodes by faecal egg counts over two years. Apart from treatment for Toxocara vitulorum at 10–16 days of age, no anthelmintics were used. Half of the strongylid egg counts were zero and 90% were less than 500 epg of faeces on the institutional farms, and 67% were zero and 97% less than 500 epg in the villages. No problems arose during four years without anthelmintics on the institutional farms and during two years in the villages. Autopsies demonstrated that the eggs which were present were produced by mixed infections of small numbers of Haemonchus spp., Mecistocirrus digitatus, Trichostrongylus spp., Bunostomum phlebotomum and Cooperia spp. High egg counts of Strongyloides papillosus occurred in calves up to six months old, but were not pathogenic.
TL;DR: In adult females the faecal egg output was not influenced by season and no significant periparturient rise was observed, and post-mortem studies on a neighbouring farm indicated that hypobiosis was not present.
Abstract: Faecal egg counts were used to study patterns of nematode infestation of adult female goats and their offspring according to season, pregnancy and lactation or age on a goat farm (n=2000) in north-western Sri Lanka. Average rainfall in the area is 825 mm and temperature is between 23 and 33°C throughout the year. The only nematode species present on the farm wereHaemonchus contortus andOesophagostomum columbianum. In adult females the faecal egg output was not influenced by season and no significant periparturient rise was observed. In kids the egg counts rose from the third month of age onwards and reached the same levels as the adults by the fourth month. Post-mortem studies on a neighbouring farm indicated that hypobiosis was not present.
TL;DR: It is concluded that (NANP)40 ELISA is potentially a valuable tool in sero-epidemiology, particularly in situations of seasonal transmission and recurrences due to drug resistance.
Abstract: An enzyme-linked immunosorbent assay (ELISA) based on the synthetic peptide (NANP)40 was used to characterize the sporozoite antibodies in an unusual Plasmodium falciparum outbreak in a non-malarious area in Sri Lanka. A positive antibody response was seen in 62% of patients with their first P. falciparum illness. There was no correlation between sporozoite antibodies and the antibody against blood stages, determined by immunofluorescence assay. The majority (91%) of the patients lost the antibodies to circumsporozoite (CS) protein within one year (in the absence of re-exposure). Three patients had high levels of CS antibodies even after one year, and this persistence was related to the level of the initial antibody response. In the area of the outbreak 10% of schoolchildren had antibodies to the (NANP)40 peptide. 21% of the 42 children with present or past overt malaria were antibody positive. Of the children with no such background, 8% were antibody positive. The corresponding seropositivity rates for asexual blood stages were 31% and 1% for the 2 groups respectively. It is concluded that (NANP)40 ELISA is potentially a valuable tool in sero-epidemiology, particularly in situations of seasonal transmission and recurrences due to drug resistance.